I have a MacBook Air (13-inch, Early 2014) and a third-party thunderbolt to vga adapter. I have had the adapter for over 2 years now and it has given me no problem at all. Suddenly, this week the macbook stopped detecting different displays. Here is what I have done to solve the problem:

  • Tried combinations of different screens, different VGA cables with the adapter
  • Checked if the adapter was working via a colleagues laptop (adapters seem to be working fine)
  • Tried different third party adapters
  • Resetting SMC and NVRAM
  • Updated the OSx from El Capitan to Mojave
  • Performed first aid and hardware check from Disk Utility
  • Tried installing the MiniDisplayVGAFirmware update

Nothing seems to work. On El Capitan the screen of the laptop would blink, after plugging the adapter to the Thunderbolt port, as if it recognised the screen but would not recognise the screen. On Mojave the screen does not even blink

I still have to try it with the official Apple Adapter but I do not want to buy it and realise that that is not the problem.

What do you think could be the issue? How can I fix it? Any suggestions would be appreciated.

Thanks in advance!

  • 1
    What you are describing is most likely a damaged MDP/Thunderbolt port. We have faculty at my school who teach in several classrooms during the course of the day, with constant plugging and unplugging of a Thunderbolt > HDMI adaptor (we use the Belkin adapter in black - more rugged than the white adaptor) and over time, the contacts in the port go bad. Under extreme circumstances, when the weight of the connecting cable is pulling the MDB plug at a downward angle, the ports can go bad quickly. – IconDaemon Sep 24 '19 at 16:29
  • I believe hardware is where the problem is then. Thanks for your help! – karts11 Sep 24 '19 at 21:34

If the adapter works fine on another Mac (second bullet point) then it is not the adapter. If you have tried a number of different adapters on your Mac and all of them do not work then I would then assume that is it one of two things:

  1. A hardware issue with your Mac. EG a bad lightning port.
  2. An issue with the installation of macOS on your Mac.

From your description of the symptoms I am leaning towards #1. However since backing up your Mac, re-formatting the HD, reinstalling the OS and restoring your files is a free (if tedious) procedure that would eliminate whether or not it is an OS issue I would start with that.

And if that fails you likely need to take the Mac in for repair.

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